In the supply of low pressure oxygen or other breathable therapeutic gas from a portable supply tank or from a fixed gas supply source in a hospital, a clear flexible plastic tube is commonly used to connect the oxygen supply tank or source to a face mask or nosepiece or tent for a patient or other person requiring the gas. Frequently, it is necessary for the patient to disconnect the flexible gas supply tube from the supply tank or gas source so that the patient may move away from the supply tank or source. This requires that the patient first shut off a valve on the supply tank or supply source. However, it has been found that all too frequently, the valve is not completely shut off, and low pressure oxygen or gas continues to leak from the source through the valve and into the room or space surrounding the gas supply. If the gas leak is not discovered and continues, the escaping gas can be dangerous and/or create an unnecessary expense.
One form of valve for use in a low pressure gas delivery system is disclosed in U.S. Pat. No. 6,189,532. This valve permits the patient to vent to atmosphere in the event gas supply diminishes or terminates. Another form of valve system is disclosed in U.S. Pat. No. 5,280,780 and is used in an oxygen delivery tube extending to a patient to prevent oxygen from being wasted during exhalation by the patient. Other forms of control valves are also used in ventilation gas apparatus or systems.